activity
20132025
most citedReconstructing the Bost--Connes semigroup actions from K-theory

4 citations · 13 across the 12 of their papers we have counts for

collaborators

12 papers

math.GR2025

Boundary actions of outer automorphism groups of Thompson-like groups

Chris Bruce, Xin Li, Takuya Takeishi

For every Cuntz--Krieger groupoid, we show that there is a topologically free boundary action of the outer automorphism group of its topological full group on the Hilbert cube. In…

math.OA2024★ 1 cited

Groupoid homology and K-theory for algebraic actions from number theory

Chris Bruce, Yosuke Kubota, Takuya Takeishi

We compute the groupoid homology for the ample groupoids associated with algebraic actions from rings of algebraic integers and integral dynamics. We derive results for the homolog…

math.OA2022

On the C*-algebra associated with the full adele ring of a number field

Chris Bruce, Takuya Takeishi

The multiplicative group of a number field acts by multiplication on the full adele ring of the field. Generalising a theorem of Laca and Raeburn, we explicitly describe the primit…

math.OA2022

Constructing number field isomorphisms from *-isomorphisms of certain crossed product C*-algebras

Chris Bruce, Takuya Takeishi

We prove that the class of crossed product C*-algebras associated with the action of the multiplicative group of a number field on its ring of finite adeles is rigid in the followi…

math.OA2021

Limits of KMS states on Toeplitz algebras of finite graphs

Takuya Takeishi

The structure of KMS states of Toeplitz algebras associated to finite graphs equipped with the gauge action is determined by an Huef--Laca--Raeburn--Sims. Their results imply that…

math.OA2021★ 2 cited

C*-dynamical invariants and Toeplitz algebras of graphs

Chris Bruce, Takuya Takeishi

In recent joint work of the authors with Laca, we precisely formulated the notion of partition function in the context of C*-dynamical systems. Here, we compute the partition funct…

math.OA2019★ 3 cited

Partition functions as C*-dynamical invariants and actions of congruence monoids

Chris Bruce, Marcelo Laca, Takuya Takeishi

We study the phase transition of KMS states for the C*-algebras of -semigroups of algebraic integers in which the multiplicative part is restricted to a congruence monoid, as…

math.OA2017★ 4 cited

Reconstructing the Bost--Connes semigroup actions from K-theory

Yosuke Kubota, Takuya Takeishi

We complete the classification of Bost--Connes systems. We show that two Bost--Connes C*-algebras for number fields are isomorphic if and only if the original semigroups actions ar…

math.OA2015

Primitive ideals and K-theoretic approach to Bost-Connes systems

Takuya Takeishi

By KMS-classification theorem, the Dedekind zeta function is an invariant of Bost-Connes systems. In this paper, we show that it is in fact an invariant of Bost-Connes -algebr…

math.OA2015

Bost-Connes systems for local fields of characteristic zero

Takuya Takeishi

The Bost-Connes system is a -dynamical system which has a relation with the class field theory. The purpose of this paper is to generalize the notion of Bost-Connes systems to…

math.OA2014★ 3 cited

Irreducible Representations of Bost-Connes systems

Takuya Takeishi

The classification problem of Bost-Connes systems was studied by Cornellissen and Marcolli partially, but still remains unsolved. In this paper, we will give a representation-theor…

math.OA2013

On Nuclearity of -algebras of Fell bundles over étale groupoids

Takuya Takeishi

In this paper, we show that if E is a Fell bundle over an amenable étale locally compact Hausdorff groupoid such that every fiber on the unit space is nuclear, then is a…